The graph of a sinusoidal function intersects its midline at (0,−2) and then has a minimum point at (23pi,−7). Write the formula of the function, where x is entered in radians.
Q. The graph of a sinusoidal function intersects its midline at (0,−2) and then has a minimum point at (23pi,−7). Write the formula of the function, where x is entered in radians.
Determine Parameters: We need to determine the amplitude, midline, period, and phase shift of the sinusoidal function. The midline is given by the y-coordinate of the point where the graph intersects the midline, which is −2. This gives us the value of D in the general equation f(x)=Acos(Bx+C)+D.
Find Amplitude: The minimum point of the function is at (3π/2,−7). Since the minimum point is 5 units below the midline (from −2 to −7), the amplitude of the function is 5. This gives us the value of A in the general equation.
Deduce Period: The period of the function is not directly given, but we can infer it from the fact that the minimum point occurs at 3π/2. Since a minimum point of a cosine function occurs at 3π/2+2πk, where k is an integer, we can deduce that the period is 2π. This gives us the value of B in the general equation, which is 1 because the period T is given by T=2π/B, so B=2π/T=2π/2π=1.
Calculate Phase Shift: The phase shift C can be determined by the fact that the graph intersects its midline at x=0. For a cosine function, this would normally happen at x=2π+2πk, but since it happens at x=0, we can deduce that there is a phase shift of −2π. This gives us the value of C in the general equation.
Write Sinusoidal Function: Now we can write the equation of the sinusoidal function using the values of A, B, C, and D that we have found. The equation is:f(x)=Acos(Bx+C)+Df(x)=5cos(1x−2π)−2
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